View source for Medicine:Human body

{{Short description|Entire structure of a human being}}
[[File:Human Body 02.png|thumb|Female (left) and male (right) adult human bodies photographed in ventral (above) and dorsal (below) perspectives. Naturally-occurring pubic, body, and facial hair have been deliberately removed to show anatomy.]]
The '''human body''' is the entire structure of a [[Biology:Human|human being]]. It is composed of many different types of [[Biology:Cell|cells]] that together create [[Biology:Tissue|tissues]] and subsequently organs and then organ systems. They ensure [[Homeostasis|homeostasis]] and the viability of the human body.

It comprises a [[Medicine:Human head|head]], hair, [[Medicine:Neck|neck]], torso (which includes the [[Biology:Thorax|thorax]] and [[Biology:Abdomen|abdomen]]), arms and hands, legs and feet.

The study of the human body includes [[Biology:Anatomy|anatomy]], [[Biology:Physiology|physiology]], [[Biology:Histology|histology]] and [[Biology:Embryology|embryology]]. The body [[Biology:Anatomical variability|varies anatomically]] in known ways. Physiology focuses on the systems and organs of the human body and their functions. Many systems and mechanisms interact in order to maintain [[Homeostasis|homeostasis]], with safe levels of substances such as sugar and [[Chemistry:Oxygen|oxygen]] in the blood.

The body is studied by [[Medicine:Health professional|health professional]]s, physiologists, anatomists, and artists to assist them in their work.

{{TOC level|3}}

==Composition==
{{Main|Biology:Composition of the human body}}
{| class="wikitable floatright"  style="font-size: 86%"
|+  align="bottom" style="text-align:left; caption-side: bottom" | Elements of the human body by mass. Trace elements are less than 1% combined (and each less than 0.1%).
| rowspan="13"|[[File:201 Elements of the Human Body.02.svg|300px]]
| style="width: 50pt;"| '''Element'''
| style="width: 10pt; text-align:center;"|'''Symbol'''
| style="width: 20pt; text-align:center;"| '''Percent mass'''
| style="width: 20pt; text-align:center;"| '''Percent atoms'''
|-
| Oxygen
| style="text-align:center;"|O
| style="text-align:right;"|65.0
| style="text-align:right;"|24.0
|-
| Carbon
| style="text-align:center;"|C
| style="text-align:right;"|18.5
| style="text-align:right;"|12.0
|-
| Hydrogen
| style="text-align:center;"|H
| style="text-align:right;"|9.5
| style="text-align:right;"|62.0
|-
| Nitrogen
| style="text-align:center;"|N
| style="text-align:right;"|3.2
| style="text-align:right;"|1.1
|-
| Calcium
| style="text-align:center;"|Ca
| style="text-align:right;"|1.5
| style="text-align:right;"|0.22
|-
| Phosphorus
| style="text-align:center;"|P
| style="text-align:right;"|1.0
| style="text-align:right;"|0.22
|-
| Potassium
| style="text-align:center;"|K
| style="text-align:right;"|0.4
| style="text-align:right;"|0.03
|-
| Sulfur
| style="text-align:center;"|S
| style="text-align:right;"|0.3
| style="text-align:right;"|0.038
|-
| Sodium
| style="text-align:center;"|Na
| style="text-align:right;"|0.2
| style="text-align:right;"|0.037
|-
| Chlorine
| style="text-align:center;"|Cl
| style="text-align:right;"|0.2
| style="text-align:right;"|0.024
|-
| Magnesium
| style="text-align:center;"|Mg
| style="text-align:right;"|0.1
| style="text-align:right;"|0.015
|-
|  Trace elements
|
| style="text-align:right;"|< 0.1
| style="text-align:right;"|< 0.3
|}

The [[Biology:Composition of the human body|human body is composed of]] [[Chemistry:Chemical element|elements]] including [[Chemistry:Hydrogen|hydrogen]], [[Chemistry:Oxygen|oxygen]], [[Chemistry:Carbon|carbon]], [[Chemistry:Calcium|calcium]] and [[Chemistry:Phosphorus|phosphorus]]. These elements reside in trillions of cells and non-cellular components of the body.

The adult male body is about 60% water for a total water content of some {{convert|42|litre}}. This is made up of about {{convert|19|litres}} of [[Biology:Extracellular fluid|extracellular fluid]] including about {{convert|3.2|litre}} of blood plasma and about {{convert|8.4|litre}} of [[Biology:Interstitial fluid|interstitial fluid]], and about {{convert|23|litre}} of fluid inside cells.<ref>{{Cite web|title=Fluid Physiology|url=http://www.anaesthesiamcq.com/FluidBook/fl2_1.php|website=Anaesthesiamcq|url-status=dead|archive-url=https://web.archive.org/web/20050503083706/http://www.anaesthesiamcq.com/FluidBook/fl2_1.php|archive-date=3 May 2005|access-date=2 September 2016}}</ref> The content, acidity and composition of the water inside and outside cells is carefully maintained. The main electrolytes in body water outside cells are [[Chemistry:Sodium|sodium]] and [[Chemistry:Chloride|chloride]], whereas within cells it is [[Chemistry:Potassium|potassium]] and other [[Chemistry:Phosphate|phosphate]]s.{{sfn|Ganong's|2016|p=5}}

===Cells===
The body contains trillions of [[Biology:Cell|cells]], the fundamental unit of life.<ref>{{Cite web |url=http://sciencenetlinks.com/student-teacher-sheets/cells-your-body/ |title=The Cells in Your Body |publisher=Science Netlinks |access-date=2 September 2016}}</ref> At maturity, there are roughly 30<ref name="sender-et-al">{{Cite journal |last1=Sender |first1=Ron |last2=Fuchs |first2=Shai |last3=Milo |first3=Ron |year=2016 |title=Revised estimates for the number of human and bacteria cells in the body |journal=PLOS Biology |volume=14 |issue=8 |pages=e1002533 |biorxiv=10.1101/036103 |doi=10.1371/journal.pbio.1002533 |pmc=4991899 |pmid=27541692 |doi-access=free }}</ref>{{ndash}}37<ref>{{Cite journal|display-authors=3 |last1=Bianconi |first1=Eva |last2=Piovesan |first2=Allison |last3=Facchin |first3=Federica |last4=Beraudi |first4=Alina |last5=Casadei |first5=Raffaella |last6=Frabetti |first6=Flavia |last7=Vitale |first7=Lorenza |last8=Pelleri |first8=Maria Chiara |last9=Tassani |first9=Simone |last10=Piva |first10=Francesco |last11=Perez-Amodio |first11=Soledad |last12=Strippoli |first12=Pierluigi |last13=Canaider |first13=Silvia|date=5 July 2013 |title=An estimation of the number of cells in the human body. |journal=Annals of Human Biology |volume=40 |issue=6 |pages=463–471 |doi=10.3109/03014460.2013.807878 |pmid=23829164 |hdl=11585/152451 |s2cid=16247166 |doi-access=free }}</ref><ref>{{Cite journal |last1=Hatton |first1=Ian A. |last2=Galbraith |first2=Eric D. |last3=Merleau |first3=Nono S. C. |last4=Miettinen |first4=Teemu P. |last5=Smith |first5=Benjamin McDonald |last6=Shander |first6=Jeffery A. |date=2023-09-26 |title=The human cell count and size distribution |journal=Proceedings of the National Academy of Sciences |language=en |volume=120 |issue=39 |pages=e2303077120 |doi=10.1073/pnas.2303077120 |issn=0027-8424 |pmc=10523466 |pmid=37722043|bibcode=2023PNAS..12003077H }}</ref>{{nbsp}}trillion cells in the body, an estimate arrived at by totaling the cell numbers of all the [[Biology:Organ|organs]] of the body and cell types. The body is also host to about the same number of non-human cells<ref name="sender-et-al" /> as well as multicellular organisms which reside in the [[Biology:Gastrointestinal tract|gastrointestinal tract]] and on the [[Biology:Human skin|skin]].<ref name="Fredericks">{{Cite journal |first=David N. |last=Fredricks |year=2001 |title=Microbial Ecology of Human Skin in Health and Disease |journal=Journal of Investigative Dermatology Symposium Proceedings |volume=6 |issue=3 |pages=167–169 |doi=10.1046/j.0022-202x.2001.00039.x |pmid=11924822|s2cid=34741925 |doi-access=free }}</ref> Not all parts of the body are made from cells. Cells sit in an [[Biology:Extracellular matrix|extracellular matrix]] that consists of [[Biology:Protein|protein]]s such as [[Biology:Collagen|collagen]], surrounded by extracellular fluids. Of the {{cvt|70|kg|lb}} weight of an average human body, nearly {{cvt|25|kg|lb}} is non-human cells or non-cellular material such as [[Biology:Bone|bone]] and connective tissue.

====Genome====
{{Main|Biology:Genome}}

Cells in the body function because of [[Biology:DNA|DNA]]. DNA sits within the [[Biology:Cell nucleus|nucleus of a cell]]. Here, parts of DNA are copied and sent to the body of the cell via [[Biology:RNA|RNA]].{{sfn|Ganong's|2016|p=16}} The RNA is then used to [[Biology:Translation|create]] [[Biology:Protein|protein]]s which form the basis for cells, their activity, and their products. Proteins dictate cell function and gene expression, a cell is able to self-regulate by the amount of proteins produced.<ref>{{Cite web|title=Gene Expression {{!}} Learn Science at Scitable|url=http://www.nature.com/scitable/topicpage/gene-expression-14121669|website=www.nature.com|language=en|url-status=dead|archive-url=https://web.archive.org/web/20101031053632/http://www.nature.com/scitable/topicpage/gene-expression-14121669|archive-date=31 October 2010|access-date=29 July 2017}}</ref> However, not all cells have DNA; some cells such as mature red blood cells lose their nucleus as they mature.

===Tissues===

The body consists of many different types of [[Biology:Tissue|tissue]], defined as cells that act with a specialised function.<ref>{{Cite web |url=https://en.oxforddictionaries.com/definition/tissue |archive-url=https://web.archive.org/web/20161005004435/https://en.oxforddictionaries.com/definition/tissue |url-status=dead |archive-date=5 October 2016 |title=tissue – definition of tissue in English |work=Oxford Dictionaries{{!}} English |access-date=17 September 2016}}</ref> The study of tissues is called [[Biology:Histology|histology]] and often occurs with a [[Engineering:Microscope|microscope]]. The body consists of four main types of tissues. These are lining cells (epithelia), connective tissue, nerve tissue and [[Biology:Muscle tissue|muscle tissue]].{{sfn|Gray's Anatomy|2008|p=27}}

Cells that lie on surfaces exposed to the outside world or gastrointestinal tract (epithelia) or internal cavities ([[Biology:Endothelium|endothelium]]) come in numerous shapes and forms – from single layers of flat cells, to cells with small beating hair-like cilia in the lungs, to column-like cells that line the [[Biology:Stomach|stomach]]. Endothelial cells are cells that line internal cavities including blood vessels and glands. Lining cells regulate what can and can not pass through them, protect internal structures, and function as sensory surfaces.{{sfn|Gray's Anatomy|2008|p=27}}

===Organs===
[[Biology:Organ|Organs]], structured collections of [[Biology:Cell|cells]] with a specific function,<ref>{{Cite web |url=http://www.collinsdictionary.com/dictionary/english/organ |title=organ {{!}} Definition, meaning & more |publisher=Collins Dictionary |website=www.collinsdictionary.com |access-date=17 September 2016}}</ref> mostly sit within the body, with the exception of [[Biology:Human skin|skin]]. Examples include the [[Biology:Heart|heart]], [[Medicine:Lung|lung]]s and [[Biology:Liver|liver]]. Many organs reside within cavities within the body. These cavities include the abdomen (which contains the stomach, for example) and pleura, which contains the lungs.

==== Heart ====
{{Main|Biology:Heart}}
The heart is an organ located in the thoracic cavity between the [[Medicine:Lung|lung]]s and slightly to the left. It is surrounded by the pericardium which holds it in place in the mediastinum and serves to protect it from blunt trauma, [[Medicine:Infection|infection]] and help lubricate the movement of the heart via [[Biology:Pericardial fluid|pericardial fluid]].<ref>{{Cite journal|last1=Jaworska-Wilczynska|first1=Maria|last2=Trzaskoma|first2=Pawel|last3=Szczepankiewicz|first3=Andrzej A.|last4=Hryniewiecki|first4=Tomasz|date=2016|title=Pericardium: structure and function in health and disease|journal=Folia Histochemica et Cytobiologica|volume=54|issue=3|pages=121–125|doi=10.5603/FHC.a2016.0014|issn=1897-5631|pmid=27654013|doi-access=free}}</ref> The heart works by [[Biology:Circulatory system|pumping blood around the body]] allowing [[Chemistry:Oxygen|oxygen]], [[Earth:Nutrient|nutrient]]s, [[Biology:Metabolic waste|waste]], [[Biology:Hormone|hormone]]s and [[Biology:White blood cell|white blood cell]]s to be transported.
[[File:Diagram of the human heart (cropped).svg|left|thumb|207x207px|Diagram of the human heart]]
The heart is composed of two atria and [[Medicine:Ventricle (heart)|two ventricles]]. The primary purpose of the atria is to allow uninterrupted venous blood flow to the heart during ventricular systole. This allows enough blood to get into the ventricles during atrial systole. Consequently, the atria allow a [[Medicine:Cardiac output|cardiac output]] roughly 75% greater than would be possible without them.<ref>{{Cite book|url=https://books.google.com/books?id=A3OmTSgtOgwC|title=The Gross Physiology of the Cardiovascular System|date=1999|first=Robert M. |last=Anderson|edition=2nd |chapter=Chapter 1: Normal Physiology |page=11}}</ref> The purpose of the ventricles is to [[Biology:Pulmonary circulation|pump blood to the lungs]] through the right ventricle and to [[Biology:Circulatory system|the rest of the body]] through the left ventricle.<ref>{{Cite web|title=Ventricle {{!}} heart|url=https://www.britannica.com/science/ventricle-heart|access-date=2021-08-07|website=Encyclopedia Britannica|language=en}}</ref>

The heart has an [[Medicine:Electrical conduction system of the heart|electrical conduction system]] to control the contractions and relaxation of the muscle. It starts in the sinoatrial node traveling through the atria causing them to pump blood into the ventricles. It then travels to the atrioventricular node which makes the signal slow down slightly allowing the ventricles to fill with blood before pumping it out and starting the cycle over again.<ref>{{Cite web|title=How the Heart Works {{!}} NHLBI, NIH|url=https://www.nhlbi.nih.gov/health-topics/how-heart-works|access-date=2021-08-07|website=www.nhlbi.nih.gov|at=Your Heart's Electrical System}}</ref>

[[Medicine:Coronary artery disease|Coronary artery disease]] is the [[Social:List of causes of death by rate|leading cause of death worldwide]], making up 16% of all deaths.<ref>{{Cite web|title=The top 10 causes of death|url=https://www.who.int/news-room/fact-sheets/detail/the-top-10-causes-of-death|access-date=2021-08-07|website=www.who.int|language=en}}</ref> It is caused by the buildup of [[Medicine:Atherosclerosis|plaque]] in the [[Biology:Coronary arteries|coronary arteries]] supplying the heart, eventually the arteries may become so narrow that [[Medicine:Ischemia|not enough blood]] is able to reach the [[Biology:Cardiac muscle|myocardium]],<ref>{{Cite web|last=CDC|date=2021-07-19|title=Coronary Artery Disease {{!}} cdc.gov|url=https://www.cdc.gov/heartdisease/coronary_ad.htm|access-date=2021-08-07|website=Centers for Disease Control and Prevention|language=en-us}}</ref> a condition known as [[Medicine:Myocardial infarction|myocardial infarction or heart attack]], this can cause [[Medicine:Heart failure|heart failure]] or [[Medicine:Cardiac arrest|cardiac arrest]] and eventually death.<ref>{{Cite web|last=CDC|date=2021-01-11|title=Heart Attack Symptoms, Risk Factors, and Recovery {{!}} cdc.gov|url=https://www.cdc.gov/heartdisease/heart_attack.htm|access-date=2021-08-07|website=Centers for Disease Control and Prevention|language=en-us}}</ref> Risk factors for coronary artery disease include obesity, smoking, high cholesterol, [[Medicine:Hypertension|high blood pressure]], [[Medicine:Sedentary lifestyle|lack of exercise]] and [[Medicine:Diabetes|diabetes]].<ref>{{Cite web|last=CDC|date=2019-12-09|title=Know Your Risk for Heart Disease {{!}} cdc.gov|url=https://www.cdc.gov/heartdisease/risk_factors.htm|access-date=2021-08-07|website=Centers for Disease Control and Prevention|language=en-us}}</ref> [[Medicine:Heart cancer|Cancer can affect the heart]], though it is exceedingly rare and has usually [[Medicine:Metastasis|metastasized]] from another part of the body such as the lungs or [[Medicine:Breast cancer|breasts]]. This is because the [[Biology:Cardiac muscle|heart cells]] quickly stop dividing and all growth occurs through [[Medicine:Hypertrophy|size increase]] rather than [[Biology:Mitosis|cell division]].<ref>{{Cite web|date=2009-02-10|title=Matters of the Heart: Why Are Cardiac Tumors So Rare? |url=https://www.cancer.gov/types/metastatic-cancer/research/cardiac-tumors|access-date=2021-08-07|website=www.cancer.gov – National Cancer Institute|language=en}}</ref>

==== Gallbladder ====
{{Main|Biology:Gallbladder}}
The gallbladder is a hollow pear shaped organ located posterior to the inferior middle part of the right lobe of the liver. It is variable in shape and size. It stores [[Biology:Bile|bile]] before it is released into the small intestine via the [[Biology:Common bile duct|common bile duct]] to help with [[Biology:Lipid metabolism|digestion of fats]]. It receives bile from the [[Biology:Liver|liver]] via the [[Biology:Cystic duct|cystic duct]] which connects to the [[Biology:Common hepatic duct|common hepatic duct]] to form the [[Biology:Common bile duct|common bile duct]].<ref name="Nagral2005">{{cite journal|last1=Nagral|first1=Sanjay|title=Anatomy relevant to cholecystectomy|journal=Journal of Minimal Access Surgery|date=2005|volume=1|issue=2|pages=53–8|doi=10.4103/0972-9941.16527|pmid=21206646|pmc=3004105 |doi-access=free }}</ref>

The gallbladder gets its blood supply from the cystic artery which in most people emerges from the right hepatic artery.<ref name="Nagral2005" />

[[Medicine:Gallstone|Gallstone]]s is a common disease in which one or more stones form in the gallbladder or [[Medicine:Biliary tract|biliary tract]]. Most people are asymptomatic but if a stone blocks the biliary tract it causes a gallbladder attack, symptoms may include sudden pain in the upper right abdomen and or center of the abdomen. Nausea and vomiting may also occur. Typical treatment is removal of the gallbladder through a procedure called a [[Medicine:Cholecystectomy|cholecystectomy]].<ref>{{Cite web|title=Gallstones – Symptoms and causes|url=https://www.mayoclinic.org/diseases-conditions/gallstones/symptoms-causes/syc-20354214|access-date=2021-08-07|website=Mayo Clinic|language=en}}</ref><ref>{{Cite web|title=Gallstones – Diagnosis and treatment |url=https://www.mayoclinic.org/diseases-conditions/gallstones/diagnosis-treatment/drc-20354220|access-date=2021-08-07|website=www.mayoclinic.org}}</ref> Having gallstones is a risk factor for [[Medicine:Gallbladder cancer|gallbladder cancer]] which although quite uncommon is rapidly fatal if not diagnosed early.<ref>{{Cite web|title=Gallbladder cancer – Symptoms and causes|url=https://www.mayoclinic.org/diseases-conditions/gallbladder-cancer/symptoms-causes/syc-20353370|access-date=2021-08-07|website=Mayo Clinic|language=en}}</ref>

===Systems===
<!--
<gallery mode=packed heights=350px>
File:Organ Systems I.jpg
File:Organ Systems II.jpg
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====Circulatory system====
{{Main|Biology:Circulatory system}}

The [[Biology:Circulatory system|circulatory system]] consists of the [[Biology:Heart|heart]] and [[Biology:Blood vessel|blood vessel]]s ([[Biology:Artery|arteries]], [[Medicine:Vein|vein]]s and [[Biology:Capillary|capillaries]]). The heart propels the circulation of the blood, which serves as a "transportation system" to transfer [[Chemistry:Oxygen|oxygen]], fuel, nutrients, waste products, immune cells and signalling molecules (i.e. hormones) from one part of the body to another. Paths of blood circulation within the human body can be divided into two circuits: the [[Biology:Pulmonary circulation|pulmonary circuit]], which pumps blood to the lungs to receive [[Chemistry:Oxygen|oxygen]] and leave [[Chemistry:Carbon dioxide|carbon dioxide]], and the systemic circuit, which carries blood from the heart off to the rest of the body. The blood consists of fluid that carries [[Biology:Cell|cells]] in the circulation, including some that move from tissue to blood vessels and back, as well as the [[Biology:Spleen|spleen]] and [[Biology:Bone marrow|bone marrow]].<ref>{{Cite news|title=Cardiovascular System|publisher=U.S. National Cancer Institute|url=http://training.seer.cancer.gov/module_anatomy/unit7_1_cardvasc_intro.html|url-status=dead|access-date=16 September 2008|archive-url=https://web.archive.org/web/20070202040248/http://www.training.seer.cancer.gov/module_anatomy/unit7_1_cardvasc_intro.html|archive-date=2 February 2007}}</ref><ref>{{Cite book |url=https://archive.org/details/humanbiologyheal00scho |title=Human Biology and Health |publisher=Pearson Prentice Hall |year=1993 |isbn=0-13-981176-1 |location=Upper Saddle River, NJ}}</ref><ref>{{Cite web |url=http://ect.downstate.edu/courseware/histomanual/cardiovascular.html |title=The Cardiovascular System |date=8 March 2008 |publisher=[[Organization:State University of New York|State University of New York]] Downstate Medical Center |access-date=16 September 2008 |archive-date=11 June 2016 |archive-url=https://web.archive.org/web/20160611213345/http://ect.downstate.edu/courseware/histomanual/cardiovascular.html |url-status=dead }}</ref>

====Digestive system====
[[File:Digestive system diagram en.svg|left|thumb|Digestive system]]
The digestive system consists of the mouth including the [[Biology:Tongue|tongue]] and teeth, [[Biology:Esophagus|esophagus]], [[Biology:Stomach|stomach]], (gastrointestinal tract, [[Biology:Small intestine|small]] and [[Biology:Large intestine|large intestine]]s, and [[Biology:Rectum|rectum]]), as well as the [[Biology:Liver|liver]], pancreas, [[Biology:Gallbladder|gallbladder]], and salivary glands. It converts food into small, nutritional, non-toxic [[Physics:Molecule|molecule]]s for distribution and absorption into the body. These molecules take the form of [[Biology:Protein|protein]]s (which are broken down into [[Chemistry:Amino acid|amino acid]]s), [[Chemistry:Fat|fat]]s, [[Chemistry:Vitamin|vitamin]]s and [[Earth:Mineral|mineral]]s (the last of which are mainly ionic rather than molecular). After being [[Biology:Swallowing|swallowed]], food moves through the [[Biology:Gastrointestinal tract|gastrointestinal tract]] by means of [[Biology:Peristalsis|peristalsis]]: the systematic expansion and contraction of muscles to push food from one area to the next.<ref>{{Cite web |url=https://www.niddk.nih.gov/health-information/health-topics/Anatomy/your-digestive-system/Pages/anatomy.aspx |title=Your Digestive System and How It Works |publisher=National Institute of Health |access-date=4 September 2016}}</ref><ref name="niddk.nih.gov">{{cite web |url=https://www.niddk.nih.gov/health-information/digestive-diseases/digestive-system-how-it-works |title=Your Digestive System & How it Works |publisher=National Institute of Diabetes and Digestive and Kidney Diseases |access-date=29 June 2019}}</ref>

Digestion begins in the [[Biology:Human mouth|mouth]], which [[Biology:Chewing|chews]] food into smaller pieces for easier digestion. Then it is [[Biology:Swallowing|swallowed]], and moves through the [[Biology:Esophagus|esophagus]] to the [[Biology:Stomach|stomach]]. In the stomach, food is mixed with [[Biology:Gastric acid|gastric acid]]s to allow the extraction of [[Earth:Nutrient|nutrient]]s. What is left is called [[Biology:Chyme|chyme]]; this then moves into the [[Biology:Small intestine|small intestine]], which absorbs the nutrients and water from the chyme. What remains passes on to the [[Biology:Large intestine|large intestine]], where it is dried to form [[Medicine:Human feces|feces]]; these are then stored in the [[Biology:Rectum|rectum]] until they are expelled through the [[Biology:Human anus|anus]].<ref name="niddk.nih.gov" />

====Endocrine system====

The endocrine system consists of the principal endocrine glands: the pituitary, [[Biology:Thyroid|thyroid]], adrenals, pancreas, parathyroids, and gonads, but nearly all organs and tissues produce specific endocrine [[Biology:Hormone|hormone]]s as well. The endocrine hormones serve as signals from one body system to another regarding an enormous array of conditions, and resulting in variety of changes of function.<ref>{{cite web|title=Hormonal (endocrine) system|url=https://www.betterhealth.vic.gov.au/health/conditionsandtreatments/hormonal-endocrine-system |publisher=Victoria State Government|access-date=4 September 2016}}</ref>

====Immune system====
{{Main|Biology:Immune system}}

The [[Biology:Immune system|immune system]] consists of the [[Biology:White blood cell|white blood cell]]s, the [[Biology:Thymus|thymus]], [[Biology:Lymph node|lymph node]]s and [[Biology:Lymph|lymph]] channels, which are also part of the [[Biology:Lymphatic system|lymphatic system]]. The immune system provides a mechanism for the body to distinguish its own cells and tissues from outside cells and substances and to neutralize or destroy the latter by using specialized proteins such as [[Biology:Antibodies|antibodies]], cytokines, and toll-like receptors, among many others.<ref>{{cite web|last1=Zimmermann|first1=Kim Ann|title=Immune System: Diseases, Disorders & Function|url=http://www.livescience.com/26579-immune-system.html|publisher=LiveScience|access-date=4 September 2016}}</ref>
[[File:Skin layers.svg|thumb|236x236px|Skin]]

====Integumentary system====

The integumentary system consists of the covering of the body (the skin), including hair and nails as well as other functionally important structures such as the [[Biology:Sweat gland|sweat gland]]s and [[Biology:Sebaceous gland|sebaceous gland]]s. The skin provides containment, structure, and protection for other organs, and serves as a major sensory interface with the outside world.<ref>{{MeSH name|Integumentary+System}}</ref><ref>{{cite book | last1=Marieb | first1=Elaine |last2=Hoehn |first2=Katja | title=Human Anatomy & Physiology | url=https://archive.org/details/humananatomyphys00mari_4 | url-access=registration | publisher=Pearson Benjamin Cummings | year=2007 | edition=7th | page=[https://archive.org/details/humananatomyphys00mari_4/page/142 142]| isbn=978-0805359107 }}</ref>

====Lymphatic system====
{{Main|Biology:Lymphatic system}}

The [[Biology:Lymphatic system|lymphatic system]] extracts, transports and metabolizes lymph, the fluid found in between cells. The lymphatic system is similar to the circulatory system in terms of both its structure and its most basic function, to carry a body fluid.<ref>{{cite web|last1=Zimmermann|first1=Kim Anne|title=Lymphatic System: Facts, Functions & Diseases|url=http://www.livescience.com/26983-lymphatic-system.html|publisher=LiveScience|access-date=4 September 2016}}</ref>

====Musculoskeletal system====

The musculoskeletal system consists of the [[Biology:Human skeleton|human skeleton]] (which includes [[Biology:Bone|bone]]s, [[Biology:Ligament|ligament]]s, [[Biology:Tendon|tendon]]s, joints and [[Biology:Cartilage|cartilage]]) and attached [[Biology:Muscle|muscle]]s. It gives the body basic structure and the ability for movement. In addition to their structural role, the larger bones in the body contain [[Biology:Bone marrow|bone marrow]], the site of production of blood cells. Also, all bones are major storage sites for [[Biology:Calcium in biology|calcium]] and [[Chemistry:Phosphate|phosphate]]. This system can be split up into the [[Biology:Muscular system|muscular system]] and the [[Biology:Human skeleton|skeletal system]].<ref>{{cite book | title=Moore's Clinically Oriented Anatomy | publisher=Lippincott Williams & Wilkins | last1=Moore |first1=Keith L. |last2=Dalley |first2=Arthur F. |last3=Agur |first3=Anne M. R. | year=2010 | location=Phildadelphia | pages=2–3 | isbn=978-1-60547-652-0}}</ref>

====Nervous system====
{{Main|Biology:Nervous system}}
[[File:Nervous system diagram.png|thumb|303x303px|Nervous system]]

The [[Biology:Nervous system|nervous system]] consists of the body's [[Biology:Neuron|neuron]]s and glial cells, which together form the nerves, ganglia and gray matter which in turn form the [[Biology:Human brain|brain]] and related structures. The brain is the organ of [[Philosophy:Thought|thought]], emotion, [[Memory|memory]], and [[Philosophy:Sensory processing|sensory processing]]; it serves many aspects of communication and controls various systems and functions. The [[Biology:Special senses|special senses]] consist of [[Philosophy:Visual perception|vision]], hearing, [[Biology:Taste|taste]], and [[Biology:Olfaction|smell]]. The [[Biology:Human eye|eyes]], [[Medicine:Ear|ear]]s, [[Biology:Tongue|tongue]], and [[Medicine:Human nose|nose]] gather information about the body's environment.<ref>{{cite encyclopedia |last1=Lagassé |first1=Paul |location=New York Detroit | title=Nervous System | encyclopedia=Columbia Encyclopedia | publisher=Columbia University Press Sold and distributed by Gale Group | edition=6th | date=2001 | isbn=978-0-7876-5015-5 | url=https://archive.org/details/columbiaencyclop00laga }}</ref>

From a structural perspective, the [[Biology:Nervous system|nervous system]] is typically subdivided into two component parts: the [[Biology:Central nervous system|central nervous system]] (CNS), composed of the brain and the [[Biology:Spinal cord|spinal cord]]; and the [[Biology:Peripheral nervous system|peripheral nervous system]] (PNS), composed of the nerves and [[Biology:Ganglion|ganglia]] outside the brain and spinal cord. The CNS is mostly responsible for organizing [[Physics:Motion|motion]], processing [[Philosophy:Sense|sensory information]], thought, memory, [[Cognition|cognition]] and other such functions.<ref name="livescience.com">{{Cite web|first1=James |last1=Horton |first2=Alina |last2=Bradford |first3=Kim Ann |last3=Zimmermann|date=2022-03-25|title=Nervous System: Facts, Function & Diseases|url=https://www.livescience.com/22665-nervous-system.html|access-date=2023-02-08|website=livescience.com|language=en}}</ref> It remains a matter of some debate whether the [[Biology:Central nervous system|CNS]] directly gives rise to [[Philosophy:Consciousness|consciousness]].{{cn|date=May 2023}} The [[Biology:Peripheral nervous system|peripheral nervous system]] (PNS) is mostly responsible for gathering information with [[Biology:Sensory neuron|sensory neuron]]s and directing body movements with motor neurons.<ref name="livescience.com"/>

From a functional perspective, the nervous system is again typically divided into two component parts: the [[Biology:Somatic nervous system|somatic nervous system]] (SNS) and the autonomic nervous system (ANS). The SNS is involved in voluntary functions like speaking and [[Philosophy:Sense|sensory processes]]. The ANS is involved in involuntary processes, such as [[Biology:Digestion|digestion]] and regulating [[Physics:Blood pressure|blood pressure]].<ref>{{Cite web|title=Visual Guide to Your Nervous System|url=https://www.webmd.com/brain/ss/slideshow-nervous-system-overview|access-date=2023-02-08|website=WebMD|language=en}}</ref>

The nervous system is subject to many different diseases. In [[Medicine:Epilepsy|epilepsy]], abnormal electrical activity in the brain can cause seizures. In multiple sclerosis, the [[Biology:Immune system|immune system]] attacks the [[Biology:Myelin|nerve linings]], damaging the nerves' ability to transmit signals. [[Medicine:Amyotrophic lateral sclerosis|Amyotrophic lateral sclerosis]] (ALS), also known as Lou Gehrig's disease, is a motor neuron disease which gradually reduces movement in patients. There are also many other diseases of the nervous system.<ref name="livescience.com"/><!--and Female?-->

====Reproductive system====
{{Main|Biology:Human reproductive system}}
The primary purpose of the reproductive system is to produce new humans in the form of children and ensure their sexual development so that they can produce new humans too. It is composed of the gonads (testicles and [[Biology:Ovary|ovaries]]) which produce [[Biology:Egg cell|eggs]] and [[Biology:Spermatozoon|sperm cells]] ([[Biology:Gamete|gamete]]s) and produce [[Biology:Sex hormone|hormones]] necessary for proper sexual development. The rest of the glands and ducts of the reproductive system are responsible for the transportation and sustaining of the gametes and to [[Medicine:Pregnancy|nurture the offspring]].<ref>{{cite web|title=Introduction to the Reproductive System|url=http://training.seer.cancer.gov/module_anatomy/unit12_1_repdt_intro.html|publisher=Epidemiology and End Results (SEER) Program|url-status=dead|archive-url=https://web.archive.org/web/20070102181148/http://training.seer.cancer.gov/module_anatomy/unit12_1_repdt_intro.html|archive-date=2 January 2007}}</ref>

The reproductive system is first stimulated by the [[Biology:Hypothalamus|hypothalamus]] during puberty which causes the ovaries and testicles to produce [[Chemistry:Testosterone|testosterone]] (male) and [[Biology:Estrogen|estrogen]] and [[Chemistry:Progesterone|progesterone]] (female). Male puberty generally occurs between the ages of 13 and 15 and is characterized by beginning of [[Biology:Spermatogenesis|sperm production]] and the development of secondary sex characteristics such as increased height and weight, broadened shoulders, pubic and [[Medicine:Facial hair|facial hair]], voice deepening and muscle development. Female puberty generally occurs between the ages of 9 and 13 and is characterized by ovulation and [[Medicine:Menstruation|menstruation]]. The growth of secondary sex characteristics, such as growth of pubic and underarm hair, breast, [[Biology:Uterus|uterine]] and [[Biology:Vagina|vagina]]l growth, widening hips and increased height and weight, also occur during the female puberty process.<ref name=":0">{{Cite web|title=Technical Issues In Reproductive Health|url=http://www.columbia.edu/itc/hs/pubhealth/modules/reproductiveHealth/anatomy.html|access-date=2021-08-07|website=www.columbia.edu}}</ref>

The external male reproductive system is made up of the [[Medicine:Human penis|penis]] and the scrotum which is a sac containing the testicles. The penis consists of the glans, and contains the urethra and urinary meatus {{ndash}} the point where urine exits the penis. The rest of the penis is called the shaft and contains most of the urethra. The glans is covered by a fold of skin called the [[Medicine:Foreskin|foreskin]], although this can be removed through circumcision.<ref name=":0" />

[[File:Human male reproductive system en.svg|left|thumb|360x360px|Internal [[Biology:Gross anatomy|gross anatomy]] of the male reproductive system]]
Internally, the male reproductive system starts in the testes where hundreds of seminiferous tubules produce [[Biology:Sperm|sperm]] which is then stored and matured into spermatozoon in the epididymis. They are then brought through the vas deferens which leads away from the testes to the seminal vesicles where the sperm cells are mixed with a [[Chemistry:Fructose|fructose]]-rich fluid from the seminal vesicles allowing the sperm to stay alive and remain healthy. It is then brought by the [[Medicine:Ejaculatory duct|ejaculatory duct]] through the [[Biology:Prostate|prostate]] and bulbourethral gland, and mixed with fluids from said glands. The fluid from the prostate helps to neutralize the acidity of the vagina and keep the sperm alive. This mixture of sperm and accessory gland fluids is called [[Biology:Semen|semen]] and is released through the urethra during [[Medicine:Ejaculation|ejaculation]]. Almost the entire internal male reproductive system works in pairs with two testes, two epididymis, two vas deferens, two seminal vesicles, two ejaculatory ducts, two bulbourethral glands, but only one prostate and urethra.<ref name=":0" /><ref>{{Cite web|title=Accessory Glands {{!}} SEER Training|url=https://www.training.seer.cancer.gov/anatomy/reproductive/male/glands.html|access-date=2021-08-07|website=www.training.seer.cancer.gov}}</ref>

[[File:Mons-pubis-anatomical-location-in-female-reproductive-system.png|thumb|External female reproductive system with mons pubis highlighted]]
The external [[Medicine:Female reproductive system|female reproductive system]], also called the [[Medicine:Vulva|vulva]], consists of the [[Biology:Mons pubis|mons pubis]], a fatty mass that covers the pubis, the labia majora (outer lips), the labia minora (inner lips), the vaginal opening which opens into the vagina and is where the penis is inserted during [[Biology:Sexual intercourse|sexual intercourse]] and [[Medicine:Childbirth|children are born]]. The urethral opening is for the urethra that carries [[Biology:Urine|urine]] from the [[Biology:Urinary bladder|bladder]] and the clitoris which contains the most sensitive nerve endings and in humans has no use other than sexual pleasure. Located between the anus and vulva is the perineum.<ref>{{Cite web|title=External Genitalia {{!}} SEER Training|url=https://www.training.seer.cancer.gov/anatomy/reproductive/female/genitalia.html|access-date=2021-08-07|website=www.training.seer.cancer.gov}}</ref><ref name=":0" />
[[File:Scheme female reproductive system-en.svg|thumb|Internal [[Biology:Gross anatomy|gross anatomy]] of the female reproductive system]]

Internally, the female reproductive system contains two ovaries, the uterus, two [[Medicine:Fallopian tube|fallopian tube]]s and the [[Medicine:Cervix|cervix]]. At birth, a female has about 700,000 [[Biology:Oocyte|oocyte]]s (the immature version of the egg cell) in both ovaries combined, although this degenerates to about 400,000 by the time puberty is reached. This is a lifetime supply, as after birth, no more oocytes are produced, compared to males where sperm cells are produced during their entire lifetime. During puberty, the [[Medicine:Menstrual cycle|menstrual cycle]] begins for the first time, in response to low estrogen and progesterone levels the hypothalamus releases [[Biology:Gonadotropin-releasing hormone|gonadotropin releasing hormone]] (GnRH). This causes the [[Medicine:Anterior pituitary|anterior pituitary gland]] to release [[Biology:Follicle-stimulating hormone|follicle-stimulating hormone]] (FSH) and [[Biology:Luteinizing hormone|luteinizing hormone]] (LH). FSH stimulates ovarian follicles to grow and one dominant follicle will eventually take over. 

As the ovarian follicle continues to grow, it releases more [[Chemistry:Estradiol|estradiol]] which stimulates LH secretion and suppresses FSH secretion, preventing further follicular growth. When LH levels are highest, the follicle ruptures releasing the ovum in a process called ovulation where it is then moved to one of the fallopian tubes. After ovulation, the portion of the follicle that remains in the ovary is transformed into a corpus luteum which continues to produce estrogen and high levels of progesterone. The progesterone causes the endometrium to grow thick, preparing it for implantation of a [[Biology:Zygote|fertilized egg]]. If fertilization occurs, the corpus luteum continues to secrete hormones until the [[Biology:Placenta|placenta]] develops enough to secrete the necessary hormones for maintaining pregnancy. Eventually, the corpus luteum will turn into a [[Biology:Corpus albicans|corpus albicans]] which is essentially scar tissue. If fertilization fails, the corpus luteum will degrade into the corpus albicans and stop secreting enough progesterone and estrogen, causing the endometrial lining to break resulting in menstruation.<ref name=":0" /><ref>{{Cite web|title=Ovaries {{!}} SEER Training|url=https://www.training.seer.cancer.gov/anatomy/reproductive/female/ovaries.html|access-date=2021-08-07|website=www.training.seer.cancer.gov}}</ref>

Many diseases affect the reproductive system such as [[Medicine:Polycystic ovary syndrome|polycystic ovary syndrome]] (PCOS) which is characterized by [[Medicine:Hyperandrogenism|elevated androgen levels]], menstrual irregularities and/or small [[Medicine:Ovarian cyst|cysts]] on one or both of the ovaries. It is a common disease affecting at least 7% of adult women. Symptoms may include excess body hair, infertility, or weight gain, [[Medicine:Pattern hair loss|male pattern baldness]].<ref>{{Cite journal|last1=Ndefo|first1=Uche Anadu|last2=Eaton|first2=Angie|last3=Green|first3=Monica Robinson|date=June 2013|title=Polycystic Ovary Syndrome|journal=Pharmacy and Therapeutics|volume=38|issue=6|pages=336–355|issn=1052-1372|pmc=3737989|pmid=23946629}}</ref><ref>{{Cite web|title=Polycystic Ovary Syndrome (PCOS)|url=https://www.hopkinsmedicine.org/health/conditions-and-diseases/polycystic-ovary-syndrome-pcos|access-date=2021-08-07|website=www.hopkinsmedicine.org|language=en}}</ref>

Another reproductive disease is [[Medicine:Testicular torsion|testicular torsion]], it occurs when the spermatic cord which holds up the testicle wraps around itself cutting off [[Medicine:Ischemia|blood flow to the testicle]]. Testicular torsion is a [[Medicine:Medical emergency|medical emergency]] and can result in testicular death or infertility if not treated immediately by physically unwrapping the spermatic cord. If the testicle has suffered severe damage, it may need to be surgically removed in a lateral [[Medicine:Orchiectomy|orchiectomy]]. The primary symptom of testicular torsion is severe [[Medicine:Testicular pain|testicular pain]] at rest, nausea and vomiting may also occur. Testicular torsion can occur at any age, although it is most common in 12-18 year olds.<ref>{{Cite journal |last=Hyun |first=Grace S. |date=2018 |title=Testicular Torsion |journal=Reviews in Urology |volume=20 |issue=2 |pages=104–106 |doi=10.3909/riu0800 |doi-broken-date=17 January 2024 |issn=1523-6161 |pmc=6168322 |pmid=30288149}}</ref><ref>{{Cite journal|last1=Ringdahl|first1=Erika|last2=Teague|first2=Lynn|date=2006-11-15|title=Testicular torsion|url=https://pubmed.ncbi.nlm.nih.gov/17137004/|journal=American Family Physician|volume=74|issue=10|pages=1739–1743|issn=0002-838X|pmid=17137004}}</ref>

[[Medicine:Sexually transmitted infection|Sexually transmitted infection]]s such as [[Medicine:Syphilis|syphilis]], [[Biology:HIV|HIV]], [[Medicine:Chlamydia|chlamydia]], [[Medicine:Human papillomavirus infection|HPV]] and [[Medicine:Genital wart|genital wart]]s are spread through sexual intercourse, including oral, vaginal, anal, and manual sex. Many of these infections can be lethal if left untreated though others are mostly [[Medicine:Benignity|harmless]].<ref>{{Cite web|date=2021-08-02|title=Sexually Transmitted Diseases – Information from CDC|url=https://www.cdc.gov/std/default.htm|access-date=2021-08-07|website=www.cdc.gov|language=en-us}}</ref><ref>{{Cite web|date=2021-06-23|title=CDC – STDs – HPV|url=https://www.cdc.gov/std/hpv/default.htm|access-date=2021-08-07|website=www.cdc.gov|language=en-us}}</ref>

Cancer can affect many parts of the reproductive system including [[Medicine:Penile cancer|the penis]], [[Medicine:Testicular cancer|testicles]], [[Medicine:Prostate cancer|prostate]], [[Medicine:Ovarian cancer|ovaries]], [[Medicine:Cervical cancer|cervix]], [[Medicine:Vaginal cancer|vagina]], [[Medicine:Fallopian tube cancer|fallopian]], [[Medicine:Uterine cancer|uterus]] and [[Medicine:Vulvar cancer|vulva]].<ref>{{Cite web|title=Reproductive Cancers {{!}} HHS Office of Population Affairs|url=https://opa.hhs.gov/reproductive-health/reproductive-cancers|access-date=2021-08-07|website=opa.hhs.gov|language=en}}</ref>

==== Respiratory system ====

The respiratory system consists of the nose, nasopharynx, trachea, and lungs. It brings oxygen from the air and excretes [[Chemistry:Carbon dioxide|carbon dioxide]] and water back into the air. First, [[Earth:Atmosphere of Earth|air]] is pulled through the trachea into the lungs by the diaphragm pushing down, which creates a [[Physics:Vacuum|vacuum]]. Air is briefly stored inside small sacs known as alveoli (sing.: alveolus) before being expelled from the lungs when the diaphragm contracts again. Each alveolus is surrounded by [[Biology:Capillary|capillaries]] carrying deoxygenated blood, which absorbs oxygen out of the air and into the bloodstream.<ref>{{cite book |last1=Maton |first1=Anthea|first2=Jean |last2= Hopkins |first3=Susan |last3=Johnson|first4=Charles William |last4= McLaughlin |first5=Maryanna Quon |last5=Warner |first6=David |last6= LaHart |first7=Jill D. |last7=Wright |title=Human Biology and Health |publisher=Prentice Hall |year=2010 |pages=108–118 |isbn=978-0-13-423435-9}}</ref><ref name="webmd.com">{{Cite web|title=Respiratory System|url=https://www.webmd.com/lung/how-we-breathe|access-date=2023-02-08|website=WebMD|language=en}}</ref>

For the respiratory system to function properly, there need to be as few impediments as possible to the movement of air within the lungs. [[Medicine:Inflammation|Inflammation]] of the lungs and excess [[Biology:Mucus|mucus]] are common sources of breathing difficulties.<ref name="webmd.com"/> In [[Medicine:Asthma|asthma]], the respiratory system is persistently inflamed, causing wheezing and/or shortness of breath. [[Medicine:Pneumonia|Pneumonia]] occurs through [[Medicine:Infection|infection]] of the alveoli, and may be caused by [[Medicine:Tuberculosis|tuberculosis]]. [[Medicine:Chronic obstructive pulmonary disease|Emphysema]], commonly a result of [[Medicine:Smoking|smoking]], is caused by damage to connections between the alveoli.<ref>{{Cite web|last=Hoffman|first=Matthew|title=Lung Diseases Overview|url=https://www.webmd.com/lung/lung-diseases-overview|access-date=2023-02-08|website=WebMD|language=en}}</ref>

====Urinary system====
[[File:Urinary System (Female).png|left|thumb|Female urinary system]]
The urinary system consists of the two kidneys, two ureters, [[Biology:Urinary bladder|bladder]], and urethra. It removes<!--excretion--> waste materials from the blood through urine, which carries a variety of waste molecules and excess [[Physics:Ion|ion]]s and water out of the body.

First, the kidneys filter the blood through their respective nephrons, removing [[Biology:Metabolic waste|waste products]] like [[Chemistry:Urea|urea]], [[Chemistry:Creatinine|creatinine]] and maintaining the [[Medicine:Electrolyte imbalance|proper balance]] of [[Physics:Electrolyte|electrolyte]]s and turning the waste products into [[Biology:Urine|urine]] by combining them with water from the blood.<ref>{{Cite web|title=The Kidneys – a Basic Guide|url=https://www.nhs.uk/Livewell/Kidneyhealth/Documents/kidney%20guide.pdf|url-status=live|archive-url=https://web.archive.org/web/20210109023755/https://www.nhs.uk/Livewell/Kidneyhealth/Documents/kidney%20guide.pdf|archive-date=January 9, 2021|access-date=August 7, 2021|website=National Health Service}}</ref> The kidneys filter about 150 quarts (170 liters) of blood daily, but most of it is returned to the blood stream with only 1-2 quarts (1-2 liters) ending up as urine.<ref>{{Cite web|title=Your Kidneys & How They Work {{!}} NIDDK|url=https://www.niddk.nih.gov/health-information/kidney-disease/kidneys-how-they-work|access-date=2021-08-07|website=National Institute of Diabetes and Digestive and Kidney Diseases|language=en-US}}</ref> The urine is brought by the ureters from the kidneys down to the [[Biology:Urinary bladder|bladder]].

The [[Biology:Smooth muscle|smooth muscle]] lining the ureter walls continuously tighten and relax through a process called [[Biology:Peristalsis|peristalsis]] to force urine away from the kidneys and down into the bladder. Small amounts of urine are released into the bladder every 10–15 seconds.

The bladder is a hollow balloon shaped organ located in the [[Biology:Pelvis|pelvis]]. It stores urine until the brain signals it to relax the urinary sphincter and release the urine into the urethra starting [[Biology:Urination|urination]].<ref>{{Cite web|title=The Urinary Tract & How It Works {{!}} NIDDK|url=https://www.niddk.nih.gov/health-information/urologic-diseases/urinary-tract-how-it-works|access-date=2021-08-07|website=National Institute of Diabetes and Digestive and Kidney Diseases|language=en-US}}</ref> A normal bladder can hold up to 16 ounces (half a liter) for 3–5 hours comfortably.

Numerous [[Medicine:Urologic disease|diseases affect the urinary system]] including [[Medicine:Kidney stone disease|kidney stones]] which are formed when materials in the urine concentrate enough to form a solid mass, [[Medicine:Urinary tract infection|urinary tract infection]]s which are infections of the urinary tract and can cause pain when urinating, frequent urination and even death if left untreated. [[Medicine:Kidney failure|Renal failure]] occurs when the kidneys fail to adequately filter waste from the blood and can lead to death if not treated with [[Engineering:Kidney dialysis|dialysis]] or [[Medicine:Kidney transplantation|kidney transplantation]].<ref>{{cite web |last1=Zimmermann |first1=Kim Ann |title=Urinary System: Facts, Functions & Diseases |url=http://www.livescience.com/27012-urinary-system.html |publisher=LiveScience |access-date=4 September 2016}}</ref> [[Medicine:Cancer|Cancer]] can affect the [[Medicine:Bladder cancer|bladder]], [[Medicine:Kidney cancer|kidneys]], [[Medicine:Urethral cancer|urethra]] and [[Medicine:Ureteral cancer|ureters]] with the latter two being far more rare.<ref>{{Cite journal|last=Yaxley|first=Julian P.|date=2016|title=Urinary tract cancers: An overview for general practice|journal=Journal of Family Medicine and Primary Care|volume=5|issue=3|pages=533–538|doi=10.4103/2249-4863.197258|issn=2249-4863|pmc=5290755|pmid=28217578 |doi-access=free }}</ref>

==Anatomy==
{{Main|Biology:Outline of human anatomy|Biology:Anatomy}}
[[File:Body cavities.jpg|thumb|left|upright=1.35|[[Biology:Body cavity|Cavities]] of human body]]

Human [[Biology:Anatomy|anatomy]] is the study of the shape and form of the human body. The human body has four limbs (two arms and two legs), a head and a [[Medicine:Neck|neck]] which connect to the torso. The body's shape is determined by a strong [[Biology:Human skeleton|skeleton]] made of [[Biology:Bone|bone]] and [[Biology:Cartilage|cartilage]], surrounded by fat (adipose tissue), muscle, connective tissue, organs, and other structures. The [[Biology:Vertebral column|spine]] at the back of the skeleton contains the flexible [[Biology:Vertebral column|vertebral column]] which surrounds the [[Biology:Spinal cord|spinal cord]], which is a collection of nerve fibres connecting the [[Biology:Human brain|brain]] to the rest of the body. [[Biology:Nerve|Nerve]]s connect the spinal cord and brain to the rest of the body. All major bones, muscles, and nerves in the body are named, with the exception of [[Biology:Anatomical variation|anatomical variation]]s such as [[Biology:Sesamoid bone|sesamoid bone]]s and [[Biology:Accessory muscle|accessory muscle]]s.

Blood vessels carry blood throughout the body, which moves because of the beating of the [[Biology:Heart|heart]]. Venules and [[Medicine:Vein|vein]]s collect blood low in oxygen from tissues throughout the body. These collect in progressively larger veins until they reach the body's two largest veins, the superior and inferior vena cava, which drain blood into the right side of the heart. From here, the blood is pumped into the [[Medicine:Lung|lung]]s where it receives oxygen and drains back into the left side of the heart. From here, it is pumped into the body's largest [[Biology:Artery|artery]], the aorta, and then progressively smaller arteries and [[Biology:Arteriole|arteriole]]s until it reaches tissue. Here blood passes from small arteries into capillaries, then small veins and the process begins again. Blood carries [[Chemistry:Oxygen|oxygen]], waste products, and [[Biology:Hormone|hormone]]s from one place in the body to another. Blood is filtered at the kidneys and [[Biology:Liver|liver]].

The body consists of a number of [[Biology:Body cavity|body cavities]], separated areas which house different organ systems. The brain and [[Biology:Central nervous system|central nervous system]] reside in an area protected from the rest of the body by the blood brain barrier. The lungs sit in the pleural cavity. The [[Chemistry:Intestine|intestine]]s, [[Biology:Liver|liver]], and [[Biology:Spleen|spleen]] sit in the abdominal cavity.

Height, weight, [[Social:Body shape|shape]] and other [[Biology:Body proportions|body proportions]] vary individually and with age and sex. Body shape is influenced by the distribution of bones, [[Biology:Muscle|muscle]] and fat tissue.<ref name="bartleby1918">{{cite web|url=http://www.bartleby.com/107/|title=Anatomy of the Human Body|date=1918|publisher=Bartleby|last1=Gray|first1=Henry|access-date=4 September 2016}}</ref>

==Physiology==
{{Main|Biology:Outline of physiology|Biology:Physiology}}

Human [[Biology:Physiology|physiology]] is the study of how the human body functions. This includes the mechanical, physical, bioelectrical, and [[Biology:Biochemistry|biochemical]] functions of humans in good health, from [[Biology:Organ|organs]] to the [[Biology:Cell|cells]] of which they are composed. The human body consists of many interacting systems of organs. These interact to maintain [[Homeostasis|homeostasis]], keeping the body in a stable state with safe levels of substances such as sugar and oxygen in the blood.<ref name=UL>{{cite web |title=What is Physiology? |url=http://www.understanding-life.org/what-physiology |publisher=Understanding Life |access-date=4 September 2016 |archive-url=https://web.archive.org/web/20170819102127/http://www.understanding-life.org/what-physiology |archive-date=19 August 2017 |url-status=dead }}</ref>

Each system contributes to homeostasis, of itself, other systems, and the entire body. Some combined systems are referred to by joint names. For example, the nervous system and the endocrine system operate together as the neuroendocrine system. The nervous system receives information from the body, and transmits this to the brain via nerve impulses and [[Biology:Neurotransmitter|neurotransmitter]]s. At the same time, the endocrine system releases hormones, such as to help regulate [[Physics:Blood pressure|blood pressure]] and volume. Together, these systems regulate the internal environment of the body, maintaining blood flow, posture, energy supply, temperature, and acid balance ([[Chemistry:PH|pH]]).<ref name=UL/>

==Development==
[[File:Little baby from Puno.jpg|thumb|Baby being carried]]

Development of the human body is the process of growth to maturity. The process begins with fertilisation, where an egg released from the [[Biology:Ovary|ovary]] of a female is penetrated by [[Biology:Sperm|sperm]]. The egg then lodges in the [[Biology:Uterus|uterus]], where an [[Biology:Embryo|embryo]] and later [[Biology:Fetus|fetus]] develop until [[Medicine:Childbirth|birth]]. Growth and development occur after birth, and include both physical and psychological development, influenced by genetic, hormonal, environmental and other factors. Development and growth continue throughout life, through childhood, [[Social:Adolescence|adolescence]], and through adulthood to [[Biology:Old age|old age]], and are referred to as the process of aging.

==Society and culture==
===Professional study===
[[File:Anatomical Male Figure Showing Heart, Lungs, and Main Arteries.jpg|thumb|left|upright|Anatomical study by [[Biography:Leonardo da Vinci|Leonardo da Vinci]] ]]

[[Medicine:Health professional|Health professional]]s learn about the human body from illustrations, models, and demonstrations. Medical and dental students in addition gain practical experience, for example by [[Biology:Dissection|dissection]] of cadavers. Human anatomy, [[Biology:Physiology|physiology]], and [[Biology:Biochemistry|biochemistry]] are basic medical sciences, generally taught to medical students in their first year at medical school.<ref name=introHGray>{{cite web | url=http://www.bartleby.com/107/1.html| title= Introduction page, "Anatomy of the Human Body". Henry Gray|year=1918| access-date =27 March 2007}}</ref><ref name="Gray">{{cite book |url=https://archive.org/details/graysanatomyanat0000unse |title=Publisher's page for Gray's Anatomy|edition= 39th |year=2004 |isbn=0-443-07168-3 |access-date=27 March 2007 |url-access=registration |last1=Drake |first1=Richard Lee |last2=Gray |first2=Henry |last3=Vogl |first3=Wayne |last4=Mitchell |first4=Adam W. M. }}</ref><ref>{{cite book |url= http://www.us.elsevierhealth.com/product.jsp?isbn=0443071683 | title=Publisher's page for Gray's Anatomy |edition=39th (US) |year=2004 |isbn=0-443-07168-3| access-date=27 March 2007 |archive-url=https://web.archive.org/web/20070209134753/http://www.us.elsevierhealth.com/product.jsp?isbn=0443071683 |archive-date=9 February 2007| last1=Drake | first1=Richard Lee | last2=Gray | first2=Henry | last3=Vogl | first3=Wayne | last4=Mitchell | first4=Adam W. M. }}</ref>

===Depiction===
[[File:Corinth stehender Mädchenakt.jpg|thumb|upright=0.6|Figure drawing by Lovis Corinth (before 1925)]]

In Western societies, the contexts for depictions of the human body include [[Information|information]], [[Art|art]] and pornography. Information includes both science and education, such as anatomical drawings. Any ambiguous image not easily fitting into one of these categories may be misinterpreted, leading to disputes.<ref name="framing">{{cite journal|title=Nudity and Framing: Classifying Art, Pornography, Information, and Ambiguity|first=Beth A.|last=Eck|journal=Sociological Forum|volume=16|issue=4|date=Dec 2001| pages=603–632| publisher=Springer| jstor=684826| doi=10.1023/A:1012862311849| s2cid=143370129}}</ref> The most contentious disputes are between fine art and erotic images, which define the legal distinction of which images are permitted or prohibited.

===History of anatomy===
{{Main|Biology:History of anatomy}}
[[File:Externarvm hvmani corporis sedivm partivmve, 1543..JPG|thumb|Two facing pages of text with woodcuts of naked male and female figures, in the ''Epitome'' by Andreas Vesalius, 1543]]

In {{wipe|Ancient Greece}}, the ''Hippocratic Corpus'' described the anatomy of the skeleton and muscles.<ref>{{cite book |last=Gillispie |first=Charles Coulston | title=Dictionary of Scientific Biography | volume=VI | pages=419–427 |year=1972 | publisher=Charles Scribner's Sons | location=New York}}</ref> The 2nd century physician Galen of Pergamum compiled classical knowledge of anatomy into a text that was used throughout the Middle Ages.<ref name=BritBrit-Galen>{{cite encyclopedia |chapter-url=https://www.britannica.com/EBchecked/topic/223895/Galen-of-Pergamum |title=Encyclopædia Britannica 2006 Ultimate Reference Suite DVD |chapter=Galen of Pergamum |first=Vivian | last=Nutton |date=12 December 2023 |author-link=Vivian Nutton}}</ref> In the [[Philosophy:Renaissance|Renaissance]], Andreas Vesalius (1514–1564) pioneered the modern study of human anatomy by dissection, writing the influential book ''De humani corporis fabrica''.<ref>{{cite web |url=http://ceb.nlm.nih.gov/proj/ttp/books.htm |title=Vesalius's ''De Humanis Corporis Fabrica'' |publisher=Archive.nlm.nih.gov |access-date=29 August 2010 }}</ref><ref>{{cite web|title=Andreas Vesalius (1514–1567)|url=http://www.ingentaconnect.com/content/apl/uivs/1999/00000012/00000003/art00002?crawler=true|date=1 May 1999|publisher=Ingentaconnect|url-status=dead|archive-url=https://web.archive.org/web/20111105145007/http://www.ingentaconnect.com/content/apl/uivs/1999/00000012/00000003/art00002?crawler=true|archive-date=5 November 2011|access-date=29 August 2010}}</ref> Anatomy advanced further with the invention of the [[Engineering:Microscope|microscope]] and the study of the cellular structure of tissues and organs.<ref name=BritMicro>{{cite encyclopedia |url=https://www.britannica.com/EBchecked/topic/22980/anatomy/283/Microscopic-anatomy |title=Microscopic anatomy |encyclopedia=[[Encyclopædia Britannica]] |access-date=14 October 2013}}</ref> Modern anatomy uses techniques such as [[Physics:Magnetic resonance imaging|magnetic resonance imaging]], [[Astronomy:X-ray computed tomography|computed tomography]], fluoroscopy and ultrasound imaging to study the body in unprecedented detail.<ref>{{cite web | url=http://www.mhhe.com/biosci/ap/foxhumphys/student/olc/h-reading1.html | title=Anatomical Imaging | publisher=McGraw Hill Higher Education | year=1998 | access-date=25 June 2013 | archive-url=https://web.archive.org/web/20160303232044/http://www.mhhe.com/biosci/ap/foxhumphys/student/olc/h-reading1.html | archive-date=3 March 2016 | url-status=dead }}</ref>

===History of physiology===

The study of human physiology began with [[Biography:Hippocrates|Hippocrates]] in Ancient Greece, around 420 BCE, and with [[Biography:Aristotle|Aristotle]] (384–322 BCE) who applied critical thinking and emphasis on the relationship between structure and function. [[Biography:Galen|Galen]] ({{Circa|126|199}}) was the first to use experiments to probe the body's functions.<ref>{{cite journal | first1=C. | last1=Fell | first2=F. | last2=Griffith Pearson| title=Thoracic Surgery Clinics: Historical Perspectives of Thoracic Anatomy | journal=Thorac Surg Clin |date=November 2007 | volume=17 | issue=4 | pages=443–448, v | doi=10.1016/j.thorsurg.2006.12.001| pmid=18271159 }}</ref> The term physiology was introduced by the French physician [[Biography:Jean Fernel|Jean Fernel]] (1497–1558). In the 17th century, William Harvey (1578–1657) described the [[Biology:Circulatory system|circulatory system]], pioneering the combination of close observation with careful experiment.<ref>{{Cite journal | first=Carl | last=Zimmer |  title=Soul Made Flesh: The Discovery of the Brain – and How It Changed the World | journal=J Clin Invest | year=2004 | volume=114 | issue=5 | pages=604 | doi=10.1172/JCI22882| pmc=514597 }}</ref> In the 19th century, physiological knowledge began to accumulate at a rapid rate with the [[Biology:Cell theory|cell theory]] of Matthias Schleiden and [[Biography:Theodor Schwann|Theodor Schwann]] in 1838, that organisms are made up of cells. Claude Bernard (1813–1878) created the concept of the ''milieu interieur'' (internal environment), which Walter Cannon (1871–1945) later said was regulated to a steady state in [[Homeostasis|homeostasis]]. In the 20th century, the physiologists Knut Schmidt-Nielsen and George Bartholomew extended their studies to [[Biology:Comparative physiology|comparative physiology]] and [[Earth:Ecophysiology|ecophysiology]].<ref>{{Cite book| last=Feder | first=Martin E. | title=New directions in ecological physiology | year=1987 | publisher={{wipe|Cambridge University Press}} | location=New York | isbn=978-0-521-34938-3 }}</ref> Most recently, [[Biology:Evolutionary physiology|evolutionary physiology]] has become a distinct subdiscipline.<ref>{{Cite journal | first1=Theodore Jr. | last1=Garland |  last2=Carter | first2=P. A. | title=Evolutionary physiology | journal=Annual Review of Physiology | year=1994 | issue=1 | pages=579–621 | url=http://www.biology.ucr.edu/people/faculty/Garland/GarlCa94.pdf | doi=10.1146/annurev.ph.56.030194.003051 | volume=56 | pmid=8010752 | access-date=20 November 2013 | archive-date=12 April 2021 | archive-url=https://web.archive.org/web/20210412150229/https://biology.ucr.edu/people/faculty/Garland/GarlCa94.pdf | url-status=dead }}</ref>

==See also==
* {{annotated link|Biology:Anatomical model}}
* {{annotated link|Philosophy:Body image}}
* {{annotated link|Biology:Cell physiology}}<!--does this need to be integrated in text?-->
* {{annotated link|Biology:Comparative physiology}}
* {{annotated link|Biology:Human physical appearance}}
* {{annotated link|Medicine:Medicine}}
* Organ system
* [[Biology:Outline of human anatomy|Outline of human anatomy]]
* ''[[Philosophy:The Birth of the Clinic|The Birth of the Clinic: An Archaeology of Medical Perception]]''

== Human body lists ==

* List of skeletal muscles of the human body
* [[Medicine:List of organs of the human body|List of organs of the human body]]
* List of distinct cell types in the adult human body
* [[Biology:List of human microbiota|List of human microbiota]]

==References==
{{Reflist}}

===Books===
* {{cite book |last1=Boitano |first1=Scott |last2=Brooks |first2=Heddwen L. |last3=Barman |first3=Susan M. |last4=Barrett |first4=Kim E. |author4-link=Kim Barrett |year=2016 |title=Ganong's Review of Medical Physiology |isbn=978-0-07-182510-8 |publisher=McGraw-Hill Education |ref=CITEREFGanong's2016 }}
* {{cite book |editor=Susan Standring |date=2008 |title=Gray's anatomy: the anatomical basis of clinical practice |edition=40th |location=London |publisher=Churchill Livingstone |isbn=978-0-8089-2371-8 |ref=CITEREFGray's Anatomy2008 }}

==External links==
* ''[https://web.archive.org/web/20140126181303/http://www.wdl.org/en/item/4299/ The Book of Humans]'' (from the late 18th and early 19th centuries) (archived 26 January 2014)
* [https://web.archive.org/web/19971210121754/http://www.innerbody.com/ Inner Body] (archived 10 December 1997)
* [http://link.library.utoronto.ca/anatomia/ Anatomia 1522–1867: Anatomical Plates from the Thomas Fisher Rare Book Library]

{{Human system and organs}}
{{Physiology types}}
{{Medicine}}

{{DEFAULTSORT:Human Body}}
[[Category:Human anatomy| ]]

{{Sourceattribution|Human body}}